Source for gnu.java.security.key.dss.DSSKey

   1: /* DSSKey.java --
   2:    Copyright 2001, 2002, 2003, 2006 Free Software Foundation, Inc.
   3: 
   4: This file is a part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2 of the License, or (at
   9: your option) any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; if not, write to the Free Software
  18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19: USA
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version.  */
  37: 
  38: 
  39: package gnu.java.security.key.dss;
  40: 
  41: import gnu.java.lang.CPStringBuilder;
  42: 
  43: import gnu.java.security.Registry;
  44: import gnu.java.security.action.GetPropertyAction;
  45: import gnu.java.security.util.FormatUtil;
  46: 
  47: import java.math.BigInteger;
  48: import java.security.AccessController;
  49: import java.security.Key;
  50: import java.security.interfaces.DSAKey;
  51: import java.security.interfaces.DSAParams;
  52: import java.security.spec.DSAParameterSpec;
  53: 
  54: /**
  55:  * A base asbtract class for both public and private DSS (Digital Signature
  56:  * Standard) keys. It encapsulates the three DSS numbers: <code>p</code>,
  57:  * <code>q</code> and <code>g</code>.
  58:  * <p>
  59:  * According to the JDK, cryptographic <i>Keys</i> all have a <i>format</i>.
  60:  * The format used in this implementation is called <i>Raw</i>, and basically
  61:  * consists of the raw byte sequences of algorithm parameters. The exact order
  62:  * of the byte sequences and the implementation details are given in each of the
  63:  * relevant <code>getEncoded()</code> methods of each of the private and
  64:  * public keys.
  65:  * <p>
  66:  * <b>IMPORTANT</b>: Under certain circumstances (e.g. in an X.509 certificate
  67:  * with inherited AlgorithmIdentifier's parameters of a SubjectPublicKeyInfo
  68:  * element) these three MPIs may be <code>null</code>.
  69:  *
  70:  * @see DSSPrivateKey#getEncoded
  71:  * @see DSSPublicKey#getEncoded
  72:  */
  73: public abstract class DSSKey
  74:     implements Key, DSAKey
  75: {
  76:   /**
  77:    * A prime modulus, where
  78:    * <code>2<sup>L-1</sup> &lt; p &lt; 2<sup>L</sup></code> for
  79:    * <code>512 &lt;= L &lt;= 1024</code> and <code>L</code> a multiple of
  80:    * <code>64</code>.
  81:    */
  82:   protected final BigInteger p;
  83: 
  84:   /**
  85:    * A prime divisor of <code>p - 1</code>, where
  86:    * <code>2<sup>159</sup> &lt; q
  87:    * &lt; 2<sup>160</sup></code>.
  88:    */
  89:   protected final BigInteger q;
  90: 
  91:   /**
  92:    * <code>g = h<sup>(p-1)</sup>/q mod p</code>, where <code>h</code> is
  93:    * any integer with <code>1 &lt; h &lt; p - 1</code> such that <code>h<sup>
  94:    * (p-1)</sup>/q mod p > 1</code> (<code>g</code>
  95:    * has order <code>q mod p
  96:    * </code>).
  97:    */
  98:   protected final BigInteger g;
  99: 
 100:   /**
 101:    * Identifier of the default encoding format to use when externalizing the key
 102:    * material.
 103:    */
 104:   protected final int defaultFormat;
 105: 
 106:   /** String representation of this key. Cached for speed. */
 107:   private transient String str;
 108: 
 109:   /**
 110:    * Trivial protected constructor.
 111:    *
 112:    * @param defaultFormat the identifier of the encoding format to use by
 113:    *          default when externalizing the key.
 114:    * @param p the DSS parameter <code>p</code>.
 115:    * @param q the DSS parameter <code>q</code>.
 116:    * @param g the DSS parameter <code>g</code>.
 117:    */
 118:   protected DSSKey(int defaultFormat, BigInteger p, BigInteger q, BigInteger g)
 119:   {
 120:     super();
 121: 
 122:     this.defaultFormat = defaultFormat <= 0 ? Registry.RAW_ENCODING_ID
 123:                                             : defaultFormat;
 124:     this.p = p;
 125:     this.q = q;
 126:     this.g = g;
 127:   }
 128: 
 129:   public DSAParams getParams()
 130:   {
 131:     return new DSAParameterSpec(p, q, g);
 132:   }
 133: 
 134:   public String getAlgorithm()
 135:   {
 136:     return Registry.DSS_KPG;
 137:   }
 138: 
 139:   /** @deprecated see getEncoded(int). */
 140:   public byte[] getEncoded()
 141:   {
 142:     return getEncoded(defaultFormat);
 143:   }
 144: 
 145:   public String getFormat()
 146:   {
 147:     return FormatUtil.getEncodingShortName(defaultFormat);
 148:   }
 149: 
 150:   /**
 151:    * Returns <code>true</code> if the designated object is an instance of
 152:    * {@link DSAKey} and has the same DSS (Digital Signature Standard) parameter
 153:    * values as this one.
 154:    * <p>
 155:    * Always returns <code>false</code> if the MPIs of this key are
 156:    * <i>inherited</i>. This may be the case when the key is re-constructed from
 157:    * an X.509 certificate with absent or NULL AlgorithmIdentifier's parameters
 158:    * field.
 159:    *
 160:    * @param obj the other non-null DSS key to compare to.
 161:    * @return <code>true</code> if the designated object is of the same type
 162:    *         and value as this one.
 163:    */
 164:   public boolean equals(Object obj)
 165:   {
 166:     if (hasInheritedParameters())
 167:       return false;
 168: 
 169:     if (obj == null)
 170:       return false;
 171: 
 172:     if (! (obj instanceof DSAKey))
 173:       return false;
 174: 
 175:     DSAKey that = (DSAKey) obj;
 176:     return p.equals(that.getParams().getP())
 177:            && q.equals(that.getParams().getQ())
 178:            && g.equals(that.getParams().getG());
 179:   }
 180: 
 181:   public String toString()
 182:   {
 183:     if (str == null)
 184:       {
 185:         String ls = (String) AccessController.doPrivileged(new GetPropertyAction("line.separator"));
 186:         CPStringBuilder sb = new CPStringBuilder(ls)
 187:             .append("defaultFormat=").append(defaultFormat).append(",")
 188:             .append(ls);
 189:         if (hasInheritedParameters())
 190:           sb.append("p=inherited,").append(ls)
 191:               .append("q=inherited,").append(ls)
 192:               .append("g=inherited");
 193:         else
 194:           sb.append("p=0x").append(p.toString(16)).append(",").append(ls)
 195:               .append("q=0x").append(q.toString(16)).append(",").append(ls)
 196:               .append("g=0x").append(g.toString(16));
 197:         str = sb.toString();
 198:       }
 199:     return str;
 200:   }
 201: 
 202:   public abstract byte[] getEncoded(int format);
 203: 
 204:   /**
 205:    * @return <code>true</code> if <code>p</code>, <code>q</code> and
 206:    *         <code>g</code> are all <code>null</code>. Returns
 207:    *         <code>false</code> otherwise.
 208:    */
 209:   public boolean hasInheritedParameters()
 210:   {
 211:     return p == null && q == null && g == null;
 212:   }
 213: }